This application is based on Japanese Patent Application No. 2000-217597, filed in Japan on Jul. 18, 2000, the contents of which are hereby incorporated by reference.
1. Field of the Invention
This invention relates to a fuel supply apparatus which is mounted on a fuel tank and supplies fuel from within the fuel tank to an internal combustion engine. In particular, it relates to a fuel supply apparatus for use on a conveyance, such as a jet ski, which repeatedly undergoes abrupt accelerations and decelerations during normal operation.
2. Description of the Related Art
FIG. 5 is a partially cross-sectional elevation of a fuel supply apparatus disclosed in Japanese Published Unexamined Utility Model Application Hei 2-11476. In this figure, element number 1 is a fuel tank which houses fuel 2. 3 is a mounting plate which seals the opening 1a of the fuel tank 1 in a liquid-tight manner, 4 is a flat bracket which is secured to the mounting plate 3 and from which is suspended a fuel pump 7. 5 is a retainer which is secured to the bracket 4 by tightening screws 6 and which works together with a cushion 8 to restrain the fuel pump 7. The fuel pump 7 discharges fuel 2 from within the fuel tank 1 through a discharge opening 7a of the fuel pump 7. The cushion 8, which acts to restrain the fuel pump 7, is disposed between the lower surface of the fuel pump 7 and the retainer 5 and is made of molded rubber or similar material which can absorb vibrations which are generated when the fuel pump 7 operates.
9 is a discharge pipe which extends from the top surface of the mounting plate 3 and leads fuel 2 which is discharged by the fuel pump 7 to outside the fuel tank 1. 10 is a joint which connects the discharge opening 7a of the fuel pump 7 to the discharge pipe 9. 11 is a suction filter which is connected to the suction port 7b of the fuel pump 7 and filters out iron powder and other debris contained in the fuel 2. 12 is a power supply connector which is disposed on the top surface of the mounting plate 3 and which supplies current from an unillustrated battery to a power supply terminal 7c of the fuel pump 7 through a current supply line 13. 14 is a return pipe which returns excess fuel which has been discharged from the discharge pipe 9 to the interior of the fuel tank 1 after it has been supplied to an unillustrated internal combustion engine.
When current is supplied from the unillustrated battery to a direct current motor (not shown) within the fuel pump 7 through the power supply connector 12, the power supply line 13, and the power supply terminal 7c and the direct current motor rotates, due to the pumping action of the fuel pump 7, fuel 2 within the fuel tank 1 is drawn through the suction filter 11. After debris such as iron powder contained in the fuel 2 is filtered out by the suction filter 11, the fuel 2 is sucked in through the suction port 7b of the fuel filter 7, and it is supplied to the internal combustion engine from the discharge port 7a through the joint 10 and the discharge pipe 9.
If a fuel supply apparatus of this type is employed in a conveyance, such as a jet ski, which repeatedly undergoes abrupt accelerations and decelerations during normal operation, the abrupt changes in velocity result in inertial forces which are proportional to the mass of the fuel supply apparatus, and particularly to the mass of the fuel pump 7 which constitutes most of the mass of the fuel supply apparatus. Abrupt accelerations and decelerations also cause movement of the fuel 2 within the fuel tank 1, and the fuel 2 applies impact forces to the bracket 4 from which the fuel pump 7 is suspended. The impact forces are also transmitted by the bracket 4 to the joint 10 which connects the discharge opening 7a of the fuel pump 7 to the discharge pipe 9, and to the power supply line 13 which supplies current to the fuel pump 7.
In contrast to a fuel tank for a passenger car, which has a relatively shallow depth, a fuel tank 1 used in a jet ski has a considerable depth compared to its horizontal dimensions, so the bracket 4 which extends into the fuel tank 1 tends to be elongated. As a result, when the above-described inertial forces and impact forces are applied to the bracket 4, the bracket 4 deforms under the resulting stresses, and the deformation of the bracket 4 may cause the suction filter 11 to contact the bottom surface of the fuel tank 1. In this situation, the fuel pump 7 may become unable to draw in fuel 2 through the suction filter 11, or the suction filter 11 may become detached from the suction port 7b, allowing unfiltered fuel 2 to enter the fuel pump 7.
Furthermore, the joint 10 and the electric power supply line 13 may be damaged by stresses caused by the impact forces resulting from movement of the fuel 2 in the fuel tank 1, with the result that the fuel pump 7 may stop working properly.
The present invention provides a fuel supply apparatus in which a fuel pump can operate normally and fuel within the fuel tank can be stably discharged to an internal combustion engine without unacceptable deformation of a bracket supporting the fuel pump within the fuel tank and without damage to a joint or a power supply line when the fuel supply apparatus is subjected to large inertial forces caused by abrupt accelerations or decelerations, or when subjected to impact forces caused by movement of fuel within the fuel tank.
According to one form of the present invention, a fuel supply apparatus includes a mounting plate installed in an opening of a fuel tank, a discharge pipe mounted on the mounting plate, a fuel pump which is disposed in the fuel tank and which discharges fuel from the fuel tank to a fuel injector or other component of an internal combustion engine through the discharge pipe, and a tubular bracket which is secured to the mounting plate and which projects into the fuel tank. The bracket has a portion which surrounds and restrains the fuel pump along an outer periphery of the fuel pump. In a preferred embodiment, the portion of the bracket which surrounds and restrains the fuel pump has a plurality of inwardly projecting portions which restrain the fuel pump along its outer periphery.
In a preferred embodiment, the bracket includes an upper portion, a middle portion, and a lower portion connected to each other, with the middle portion having dimensions appropriate for the depth of the fuel tank.
The bracket may be equipped with one or more holes in a lateral surface thereof through which fuel can pass to permit fuel to enter into the interior of the bracket.
In a preferred embodiment, a joint which connects the discharge opening of the fuel pump to a discharge pipe which leads fuel to the outside of the fuel tank, and a power supply line which supplies electric current to the fuel pump are disposed in a space formed inside the bracket between the fuel pump and the mounting plate.
In another preferred embodiment, a fuel filter which filters fuel which is discharged to a fuel injector, for example, of an internal combustion engine and a pressure regulator which regulates the pressure of the fuel which is discharged to the fuel injector are disposed in the space formed inside the bracket between the fuel pump and the mounting plate.
The fuel supply apparatus may include a suspension disposed between the bracket and the bottom surface of the fuel tank for absorbing stresses applied to the fuel supply apparatus.
In a preferred embodiment, the suspension includes a spring which carries out elongation and contraction when an external stress is applied, a spring holder which holds the spring, a shaft which reciprocates with respect to the bracket as the spring elongates and contracts, and a guide on the bracket which slidably engages the guide shaft.